Electricity has now become, in the words of a dis tinguished physicist a truly imperial science, in which physics and chemistry may be said to occupy the position of mere subordinate provinces. Clerk Maxwell, Hertz, and others have shown that the medium which transmits the waves of light is identical with that which conveys the waves of electric energy. The waves of light, in fact, differ only in their extreme minuteness, and their extreme rapidity from the electric waves produced by an alternating current dynamo machine or an induction coil, and the ?ame of a candle or of a gas jet, in which electric oscillations are caused by the impact of atoms has as good a claim to be called electric light, as the glow Of the incandescent carbon filament or of the electric arc, in which identical oscillations are generated by the passage Of the So-called electric current.